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Español5 Common Mistakes When Using Switching Mode Power Supplies in Industrial Systems
In industrial environments where uptime, safety, and efficiency are critical, the switching mode power supply (SMPS) plays a vital role. Whether it powers a fire control panel, automated gate, or PLC controller, the SMPS is expected to deliver stable and efficient DC power day after day. But despite its advantages, many engineers and technicians still encounter preventable issues when using SMPS in industrial systems.
In this article, we explore five of the most common mistakes made when selecting, installing, or maintaining SMPS in industrial applications, and how you can avoid them to ensure long-term reliability and performance.
Table of Contents
Are You Sizing Your Switching Mode Power Supply with Enough Margin?
How Can Poor Ventilation Impact the Reliability of Your SMPS?
Is Your Switching Mode Power Supply Causing Electromagnetic Interference?
Are You Using the Right SMPS for Your Battery Backup System?
What Happens When You Don't Build Redundancy into Your Industrial SMPS Setup?
Why NVVV Is a Trusted Partner for Industrial SMPS Solutions
Are You Sizing Your Switching Mode Power Supply with Enough Margin?
A surprisingly common mistake in industrial SMPS usage is selecting a power supply with insufficient headroom. While it may seem efficient to match the output wattage closely to the system’s load requirements, real-world operation often includes startup surges, transient peaks, and future expansion that push the power supply beyond its limits.
For instance, in motor-driven systems or those involving relays, solenoids, or valves, the initial power draw may temporarily exceed normal levels. If the SMPS is operating near 100% capacity, this can lead to overcurrent protection triggering, system resets, or even permanent stress-related damage to the unit.
In an automated warehouse using multiple conveyor belts, engineers noticed intermittent halts during shift changes. Investigation revealed that all systems rebooted at once, causing a brief current spike that overloaded the power supply. Replacing it with an SMPS rated 30% above peak load eliminated the issue completely.
Best practice: Always size your SMPS with at least a 20–30% buffer above the calculated maximum load. This not only absorbs momentary inrush currents but also extends the lifespan of the supply by allowing it to operate at lower thermal and electrical stress.
How Can Poor Ventilation Impact the Reliability of Your SMPS?
Even though switch mode power supplies are much more efficient than linear models, they still generate heat, especially under full load or in high-ambient environments. A common oversight is installing an SMPS inside a sealed or poorly ventilated enclosure, alongside other heat-generating devices, without considering temperature buildup.
In an industrial HVAC control cabinet located near a rooftop air handling unit, the SMPS operated in direct sunlight with minimal airflow. Although rated for 240W, the unit began overheating during the summer months, leading to random shutdowns. The problem wasn't the SMPS itself—it was lack of ventilation. Once the cabinet was fitted with passive ventilation grilles and the SMPS load was derated slightly, operation stabilized.
Best practice: Always review the derating curve provided in the SMPS datasheet—it shows how much power the supply can deliver at different temperatures. If the ambient temperature approaches the upper limit, reduce the load accordingly, or select a higher-rated or fan-assisted model. For outdoor or high-dust environments, fanless designs with wide operating ranges are often a safer long-term choice.
Is Your Switching Mode Power Supply Causing Electromagnetic Interference?
SMPS operate by rapidly switching transistors—often at tens or hundreds of kilohertz. While this makes them compact and efficient, it also introduces high-frequency electrical noise. In industrial control panels, where analog signals, communication buses, or sensors are used, EMI can cause subtle but serious issues.
A bottling plant faced recurring false signals from its level sensors. After replacing the sensors and rewiring the control system to no avail, the team discovered that a newly installed SMPS, placed too close to the analog input terminals, was the source of interference. Switching to a low-noise SMPS model with proper shielding and rerouting the signal cables resolved the issue.
Best practice: Ensure your SMPS meets EMC standards (such as EN61000 or CISPR 32), especially if used near sensitive electronics. Separate signal and power paths physically inside the cabinet, use shielded cables when needed, and ground the SMPS chassis properly. When dealing with mixed-voltage systems (e.g., 24V DC power with 4–20mA sensors), physical layout and grounding are just as important as power quality.
Are You Using the Right SMPS for Your Battery Backup System?
Many industrial systems require uninterrupted power, particularly for fire detection, emergency communication, or access control. SMPS often work in tandem with battery backups, but issues arise when the batteries and power supplies are not properly matched in terms of charging voltage, current profile, or chemistry.
In a hospital fire panel system, a backup battery bank was added to maintain operation during outages. However, the SMPS used had a fixed float voltage meant for sealed lead-acid batteries, while the new batteries were lithium-based. Over time, this mismatch caused reduced charge cycles and system alarms. Upgrading to an SMPS with adjustable output voltage and proper battery management features restored compatibility and reliability.
Best practice: Check the float and charge voltage requirements of your battery type (e.g., 13.8V for SLA, 14.4V+ for Li-ion). Some SMPS models include dip switches or potentiometers for fine-tuning voltage, while others offer programmable logic interfaces to adapt to smart battery packs. Ensuring compatibility prevents both underperformance and safety hazards—especially in regulated systems like fire or security infrastructure.
What Happens When You Don't Build Redundancy into Your Industrial SMPS Setup?
In critical systems—like fire pump controllers, ventilation for data centers, or industrial elevators—a single point of failure in power delivery is simply unacceptable. Yet, many installations still rely on a single switched-mode power supply, with no redundancy or switchover capability in the event of a fault.
This becomes especially problematic during maintenance. For example, in a high-rise building’s fire suppression system, a routine power check required full shutdown, since the SMPS couldn’t be replaced without powering off the entire panel. After an incident involving delayed fire alarm response, the system was upgraded to include dual-redundant SMPS modules with ORing diodes, allowing for hot-swappable maintenance.
Best practice: For mission-critical applications, design for N+1 redundancy using two or more SMPS units in parallel. Some models support parallel current sharing and include redundancy modules for fault-tolerant operation. Even if only one unit is active at a time, redundancy ensures that a single failure doesn’t compromise system safety or uptime.
SMPS Is Reliable—If You Use It Right
The switching power supply is a foundational component in modern industrial power systems. But like any critical technology, its performance depends on how well it's understood, installed, and maintained.
By avoiding these five common mistakes—undersizing, poor ventilation, ignoring EMI, mismatched backup systems, and lack of redundancy—you’ll get the most out of your SMPS investment, reduce failure rates, and improve system safety and uptime.
Why NVVV Is a Trusted Partner for Industrial SMPS Solutions
With 20+ years of experience in industrial power supply development, NVVV provides robust, efficient, and globally certified SMPS products that meet the demands of real-world applications. Whether you're upgrading a fire control system, powering industrial automation, or designing energy-efficient backup circuits, NVVV has the products and support to help you build it right from the start.
